US5388748A - Electric powered apparatus for dispensing individual plastic fasteners from fastener stock - Google Patents

Abstract

An apparatus for dispensing plastic fasteners from fastener stock includes a gun shaped casing. A hollow needle having an inlet opening is mounted on the casing. A guide groove is formed on the casing for receiving the fastener stock, the guide groove being in communication with said inlet opening in said hollow needle. A feeder element for intermittently advancing fastener stock loaded into the guide groove is mounted on the casing. An ejector rod is provided for pushing plastic fasteners from the fastener stock through and out of the hollow needle one at a time. The ejector rod and feeder element are driven by an electric motor powered by a battery pack removably mounted in the casing and which contains rechargeable batteries. The battery pack includes a receptacle which is arranged to enable the batteries to be recharged with the battery pack in or out of the tool. A converter assembly is provided for converting rotary motion of the drive shaft of the motor into linear motion of the ejector rod, the converter assembly including a worm on the drive shaft, a worm gear driven by the worm, a spur gear loosely coupled to the worm gear, a slider for holding the ejector rod and a rack driven by the spur gear and mounted on the slider. First and second single pole double throw switches are provided for controlling the operation of said electric motor so as to either cause rotation of the drive shaft in one direction, cause rotation of the drive shaft in the other direction or stop rotation of the drive shaft. The first switch is operated by a trigger which is pivotally mounted on the casing and the second switch is operated by an actuator moved by a slide bar which is moved by the slider.

Description

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of pending U.S. patent application Ser. No. 08/061,210 filed in the names of Paul A. Davignon and Richard M. Bastien on May 13, 1993 and assigned to Avery Dennison Corporation, the assignee of this application now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to a new and improved apparatus for dispensing individual plastic fasteners from fastener stock.

Plastic fasteners of the type having a cross bar at one end, a paddle at the other end and a thin filament or cross-link connecting the two ends are well known in the art and widely used in commerce to attach labels, price tags or other items to articles in a manner which minimizes the risk of inadvertent detachment therefrom. Typically, such plastic fasteners are manufactured in the form of fastener stock, the fastener stock being produced by molding or stamping from flexible plastic materials, such as nylon, polyethylene, and polypropylene. In one known type of fastener stock, the cross bar end of each fastener is connected to a runner bar to form a clip of fasteners. In another known type of fastener stock, often referred to as ladder stock, a pair of elongated side members are interconnected by a plurality of cross links or filaments. One of the side members is shaped to define a plurality of cross bars which are joined together by short severable connectors, the connectors being defined by indentations or notches formed along the side member. The other side member is shaped to define a plurality of paddles.

Additional information pertaining to fastener stock may be obtained from the following commonly assigned U.S. patents, all of which are incorporated herein by reference: U.S. Pat. Nos. 4,955.475 issued Sep. 11, 1990; 4,456,161, issued Jun. 26, 1984; 4,121,487, issued Oct. 24, 1978; 3,470,834, issued Oct. 7, 1969 and 3,103,666, issued Sep. 17, 1963.

The dispensing of individual fasteners from fastener stock is often accomplished with an apparatus commonly referred to as a "tagger gun". Typically, a tagger gun is a hand held trigger operated gun shaped device which is constructed to accept fastener stock and which includes a mechanism for feeding the cross bar end of a fastener into a hollow needle at the front end of the gun and a mechanism for pushing the cross bar end of the fastener that has been fed into the hollow needle out through the tip of the hollow needle.

In commonly assigned U.S. Pat. No. 5,024,365, which issued Jun. 18, 1991 and which is herein incorporated by reference, a tagger gun for dispensing a plastic fastener through a slotted hollow needle from continuously connected fastener stock is described. The apparatus includes an actuator slide with a central channel, the actuator slide being secured to an ejector rod and fastener stock feed mechanism to actuate these functions. The apparatus further includes a shuttle assembly which reciprocates transversely to the needle axis to cause the cutting of a fastener from the fastener stock, and transport of the severed fastener to the needle axis. The cam bar is linked to the shuttle mechanism and pivotally mounted so that the pivoting of the cam bar causes the transverse shuttle motion. The cam bar passes through the actuator slide channel, whereby sliding of the actuator slide causes pivoting of the cam bar according to the profile of the cam. The apparatus, further includes an antiback mechanism in the form of a catch lever which engages the trigger when it has been partially depressed and prevents its release, until the trigger has been fully depressed.

In commonly assigned U.S. Pat. No. 4,456,161, which issued Jun. 26, 1984, another tagger gun for dispensing fasteners is described. The apparatus comprises a casing, a fastener dispensing hollow slotted needle mounted on the casing, means for advancing a fastener to a position adjacent the rear of the needle bore with its end-bar transversely disposed to the longitudinal axis of the bore, means for aligning the end-bar with the needle bore, and means for dispensing the end-bar through the bore. Preferably, the apparatus comprises a feed wheel, an aligning means comprising a reciprocating cam slide which also actuates the feed wheel, a dispensing means comprising a plunger carried by a reciprocating support which also actuates the cam slide, and means for reciprocating the support.

In U.S. Pat. No. 4,971,238 which issued on Nov. 20, 1990, there is disclosed a tagger gun type apparatus in which the transverse bar of a tag pin is pushed out of a hollow needle by a piston which is driven by a motor. The motor is coupled to the piston by a rack and pinion and is controlled by a circuit which includes three switches and other componentry.

In commonly assigned U.S. Pat. No. 3,470,834, which issued Oct. 7, 1969, there is disclosed an apparatus for dispensing fasteners which comprises a casing, a needle projecting from the casing, the needle having a central bore, and a plunger slidable back and forth in the bore, the needle comprising an elongated piece of sheet material bent into a tube with its edges spaced apart to provide a longitudinal slot along one side of said bore, the forward end of the needle being pointed and the rearward end having a tail for securing the needle in the aforesaid casing, the diameter of said bore being slightly larger than that of said bar so that the bar may slide lengthwise in the needle with said filament extending through said slot, and the device having a fastener passageway in advance of said plunger when the plunger is retracted.

In commonly assigned U.S. Pat. No. 4,121,487 which issued on Oct. 24, 1978 there is disclosed an apparatus for dispensing fasteners which includes a stepper motor.

In commonly assigned U.S. Pat. No. 3,103,660 issued on Sep. 17, 1963 there is described a tagger gun type apparatus for attaching tags to fabrics with a bar-lock attachment, the apparatus being adapted for utilizing plural assemblies of bar-lock attachments and comprising a hollow needle elongately slotted along one side, a plunger for driving the bar of a bar-lock attachment through the needle with the filament of the attachment projecting through the slot, feeding means for bringing each of an assembly of bar-lock attachments into register with one end of the needle, knife means for severing an attachment which is in register with the needle from an assembly of attachments, and handle means for supporting the needle, the handle means including means for operating the feeding means, the knife means and the plunger in sequence.

Another known tagger gun is the Taggetron 770, an electric powered rechargeable apparatus marketed by Central Notion Co., Inc. of Brooklyn, N.Y. Still another known tagger gun is the Taggetron 880, a modification of the Taggetron 770.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a new and improved apparatus for dispensing plastic fasteners from fastener stock.

It is another object of the present invention to provide an apparatus as described above which includes an ejector rod for pushing individual plastic fasteners out through a hollow needle and an electric motor for driving the ejector rod.

It is still yet another object of the present invention to provide an apparatus as described above which has a minimal number of parts, is extremely fast, is easy to assemble and is inexpensive to manufacture.

It is a further object of this invention to provide an apparatus as described above which includes a new and novel battery pack for powering the electric motor.

An apparatus for dispensing plastic fasteners from a clip of fastener stock constructed according to the teachings of this invention includes a casing, a hollow needle mounted at a front end portion of said casing, said hollow needle having an inlet opening for receiving the cross bar end of a fastener to be dispensed, a guide groove in said casing for receiving the fastener stock, said guide groove being in communication with said inlet opening in said hollow needle, a feeder element for intermittently advancing the fastener stock loaded into said guide groove so that the cross bar of the fastener to be dispensed is loaded into said hollow needle, an ejector rod for pushing the cross bar loaded into the hollow needle through and out of the tip of hollow needle, an electric motor for driving said ejector rod and said feeder element, said electric motor having a drive shaft, a converter assembly for converting rotary motion of the drive shaft of said electric motor into linear motion of said ejector rod, and control means for controlling the operation of said electric motor so as to produce intermittent reciprocating linear movement of said ejector rod.

According to one feature of the invention the converter assembly includes a worm mounted on the drive shaft of the electric motor, a slider, a rack mounted on the slider, a worm gear in engagement with the worm and a spur gear in engagement with the rack and coupled to the worm gear, the converter assembly being constructed so as to provide for overtravel.

According to another feature of the invention the control means includes a pair of switches constructed and arranged so as to collectively operate to either cause rotation of the drive shaft of the electric motor in one direction, cause rotation of the drive shaft of the electric motor in the other direction or stop rotation of the drive shaft of the electric motor.

According to still another feature of the invention the electric motor is powered by a battery pack which is removable and which includes rechargeable batteries. The battery pack is constructed so that the batteries can be recharged while the battery pack is either in the casing of the apparatus or removed from the casing.

According to a further feature of the invention, one of the switches in the control means is actuated by an actuator button moved by or integral with a slide bar which is moved by the slider.

According to still a further feature of the invention an arrangement is provided for manually moving the slide bar in the event of a jam in the internal mechanism of the apparatus.

Additional objects, as well as features and advantages, of the present invention will be set forth in part in the description which follows, and in part will be obvious from the description or may be learned by practice of the invention. In the description, reference is made to the accompanying drawings which form a part thereof and in which is shown by way of illustration specific embodiments for practicing the invention. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. The following detailed description is therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings wherein like reference numerals represent like parts:

FIGS. 1 and 2 are side and front views, respectively, of a clip of fastener stock which may be used with the apparatus of this invention;

FIGS. 3 and 4 are top and side views, respectively, of an apparatus constructed according to this invention for dispensing plastic fasteners using the clip of fastener stock shown in FIGS. 1 and 2;

FIG. 5 is a view illustrating the internal construction of the apparatus of this invention;

FIG. 5A is a perspective view of the apparatus as shown in FIG. 5 without the battery pack and the link connecting the slide bar to the feeder element;

FIGS. 6A and 6B taken together are an exploded view of the apparatus of this invention;

FIG. 6C is an enlarged perspective view of the release button shown in FIG. 6A;

FIG. 6D is an enlarged perspective view of the link shown in FIG. 6A;

FIGS. 7A, 7B and 7C are bottom, right side and perspective views, respectively of the battery pack in FIG. 5, the bottom wall of the casing of the battery pack being removed in FIG. 7A;

FIG. 7D is a circuit diagram for the battery pack shown in FIG. 5;

FIG. 7E is an enlarged pictorial view of the converter assembly, ejector rod and DC motor shown in FIGS. 5 and 6;

FIGS. 8, 9, 10 and 11 are front, top side and bottom views, respectively, of the slider assembly in the apparatus of this invention, FIG. 8 being broken away in part;

FIG. 12, 13 and 14 are front, top and side views, respectively, of the slide bar in the apparatus of this invention;

FIG. 15 is a fragmentary top view of a portion of the apparatus of this invention;

FIG. 15A is a simplified top view of the slider and slide bar in FIG. 15;

FIG. 16 is a circuit diagram of the electrical portion of the apparatus of this invention;

FIGS. 17, 18 and 19 are front section, top and side views of another embodiment of the battery pack in the apparatus of this invention;

FIG. 20 is circuit diagram for the battery pack in FIG. 17;

FIG. 21 is a perspective view of a modification of the actuator and slide bar shown in FIG. 5A; and

FIG. 22 is a perspective view of a modification of the actuator shown in FIG. 5A.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to the drawings, there are shown in FIGS. 1 and 2 side and front views, respectively, of a length of one type of known fastener stock, the fastener stock being identified by reference numeral 11. As can be seen, fastener stock 11 includes a plurality ofindividual fasteners 13, each having across bar 15 at one end, apaddle 17 at the other end and athin filament 19 connecting the two ends. Eachfastener 13 is coupled to acommon runner 20 through ashort connector filament 21 at the cross bar end of thefastener 13. Clip 11 is made of a plastic such as nylon, polyethylene or polypropylene.

Referring now to FIGS. 3 and 4., there are shown top and side views, respectively, of an apparatus constructed according to this invention for dispensingplastic fasteners 13 from fastener stock 11, the apparatus being identified byreference numeral 23. The internal structure ofapparatus 23 is shown in FIGS. 5, 5A and 6A through 6C and 7A through 7D.

Apparatus 23 includes a hollow gun-shaped casing 25 having ahandle portion 27 and abarrel portion 29. Casing 25 is formed of aright half 31 and aleft half 33.Body half 31 includes five elongated ribs 31-1, 31-2, 31-3, 31-4 and 31-5.Halves 31 and 33 may be fabricated from any convenient material, such as molded plastic and are joined together byscrews 35. Alternatively, halves 31 and 33 may be joined together by a snap-fit, by sonic welding, by gluing, by riveting or the like.Apparatus 23 is hand actuated by alever type trigger 37 located at the front ofhandle portion 27. Aguide groove 39 is formed in the top ofbarrel portion 29 into which fastener stock 11 is inserted. Ahollow needle 40 is removably mounted in an opening 40-1 at thefront end 41 ofbarrel portion 29.Needle 40 includes aninlet opening 42 for receiving thecross bar 15 of afastener 13. In the operation ofapparatus 23, fastener stock 11 is inserted intogroove 39 ofapparatus 23. Thecross bar 15 of afastener 13 to be dispensed is fed intoneedle 40 through inlet opening 42 and is then pushed out through tip 42-1 ofneedle 42 as will hereinafter be described.Needle 40 includes aknife edge 43 at the back which serves to separate afastener 13 from the fastener stock 11 as it is fed intohollow needle 40. Anantiback 44 is pivotally mounted on apin 45 on casing 25 to prevent fastener stock 11 from backing up inguide groove 39 up during the feed operation.

Trigger 37 is pivotally mounted on apivot pin 46 integrally formed onright half 31 of casing 25.Trigger 37 is held biased outward by acompression spring 47 sandwiched between a U shapedrib 48 formed inhandle portion 27 and a U shapedrib 49 formed inright half 31 of casing 25. Whentrigger 37 is pushed in,projection 51 at the bottom oftrigger 37 will hit up against and push in abutton 53 on afirst switch 55.

An L-shapedejector rod 57 is provided for pushing cross bars 15 offasteners 13 out throughhollow needle 41, one at a time.Ejector rod 57 is driven by aDC motor 59 which is mounted on supports 59-1 and 59-2 integrally formed onright half 31 of casing 25.DC motor 59 is powered by aremovable battery pack 60.

Battery pack 60, which is shown separately in FIGS. 7A through 7C, includes a set of batteries 60-1, 60-2 and 60-3 which are disposed inside a generally box shaped container 60-4 having a bottom wall 60-5 and an open top 60-6, a spacer 60-7, a pair of terminals 60-8 and 60-9, a cover plate 60-10 and a switch type charging receptacle 60-11. Cover plate 60-10 is secured to the top of the box shaped container 60-4 by an adhesive or any other suitable means such as screws.Battery pack 60 is slidably mounted into casing 25 from the back as shown by arrows A in FIG. 5A. An elongated generally rectangular flexible tab 60-12 on container 60-4 holdsbattery pack 60 in place in casing 25. Charging receptacle 60-11 is accessed through an opening 60-13 extending in from bottom 60-5. Charging receptacle 11 includes a normally closed negative terminal 60-14, a fixed negative terminal 60-15 and a fixed positive terminal 60-16.

A circuit diagram forbattery pack 60 is shown in FIG. 7D.

Whenbattery pack 60 is not being charged i.e. the plug of a charging device (not shown) is not inserted into charging receptacle 60-11, terminal 60-14 is closed and batteries 60-1, 60-2 and 60-3 will be coupled in to output terminals 60-8 and 60-9 through junction 60-17 on one side and contacts 6-14 and 60-15 on the other side as shown by dashed lines D. When the plug of a charging device is inserted into receptacle 60-11, normally closed negative contact 60-14 will be pushed open and batteries 60-1, 60-2 and 60-3 will be coupled to the charging device through a path including positive terminal 60-16 and junction 60-17 on one side and negative terminal 60-15 on the other side as shown by dashed lines E. When the plug of the charging device is so inserted into charging receptacle 60-11, batteries 60-1, 60-2 and 60-3 will not be coupled to output terminals 60-8 and 60-9.

As can be appreciated,battery pack 60 can be recharged either while it is in casing 25 or is removed from casing 25.

Rotation of thedrive shaft 61 ofDC motor 59 is converted into linear movement ofejector rod 57 by aconverter assembly 63. Rotation ofdrive shaft 61 is reversed to produce reciprocating linear movement ofejector rod 57 by a switch arrangement as will be later described. An enlarged pictorial view ofconverter assembly 63,ejector rod 57 andDC motor 59 is shown in FIG. 7E.

Converter assembly 63 includes aworm 65 fixedly mounted on aspline 67 attached to thefront end 69drive shaft 61 ofDC motor 59 and held in place by abushing 71, aworm gear 73 in engagement withworm 65, aspur gear 75 in engagement withworm gear 73 and aslider assembly 76.

Separate views ofslider assembly 76 are also shown in FIGS. 8 through 11.Slider assembly 76 includes aslider 77, arack 79 and a pair of compression springs 81 and 83.Ejector rod 57 is mounted in a hole 83-1 inslider 77. Thus, back and forth movement ofslider 77 will result in back and forth movement ofejector rod 57.Rack 79 is snap-fit into arecess 84 inslider 77.Rack 77 is slidably movable inrecess 84 inslider 77 as shown by arrows A in FIG. 7 and is in engagement withspur gear 75 unless disengaged as will hereinafter be explained.Slider 77 is mounted in casing 25 for slidable movement back and forth withinbarrel portion 29 along rib 31-4 onbody half 31 as shown by arrows B in FIG. 5. Movement ofrack 79 inslider 77 is restricted by compression springs 81 and 83.Compression spring 81 is disposed insiderack 79 between astop 85 at the front end ofrack 79 and acenter post 87 onslider 77.Compression spring 83 is disposed insiderack 79 between astop 89 at the rear end ofrack 79 andcenter post 87.

Forward movement ofslider 77 in casing 25 is limited by afront stop 90 integrally formed inright half 31 of casing 25 while rearward travel ofslider 77 is limited by arear stop 91 formed inright half 31 of casing 25. In order to prevent jamming of the gears at each end of travel ofslider 77,rack 79 is sized to provide for overtravel. In particular, the number of teeth and length ofrack 79 is such thatrack 79 will disengage from spur gear 75 (i.e. run out of teeth) at the end of its travel in each direction. Momentum will cause continued movement ofrack 79 withinslider 77, independent ofspur gear 75. Reengagement ofrack 79 withspur gear 75 is achieved by compression springs 81 and 83 as will also hereinafter be explained in more detail.

Worm gear 73 andspur gear 75 are each rotably mounted on ashaft 93 which is fixedly mounted inright half 31 of casing 25.Worm gear 73 is located behindspur gear 75. For clarity,spur gear 75 is broken away partly in FIG. 5 to showworm gear 73.Worm gear 73 andspur gear 75 are coupled together for movement by a set ofsplines 95 integrally formed on the front side ofworm gear 73 and which face and interlock in a loose manner with a set ofsplines 97 integrally formed on one side ofspur gear 75. The loose interconnection ofworm gear 73 to spurgear 75 allows for overtravel ofworm gear 73 relative to spurgear 75. This overtravel enablesmotor 59 to drivespur gear 75 to a high speed very quickly and with very little torque. The overtravel is realized by sizing and spacing the splines on each gear soworm gear 73 will have to rotate at least a few degrees in either direction before its splines hit up against the splines in thespur gear 75 and causespur gear 75 to rotate with it.

Areciprocating feed pawl 99 for advancing fastener stock 11 loaded intoguide groove 39 is rotably mounted onpin 45 in front ofantiback 44.Feed pawl 99 is driven by aslide bar 103 which is coupled to feedpawl 99 by a generallyU-shaped link 105. One end oflink 105 is mounted in a hole 103-1 inslide bar 103 and the other end oflink 105 is mounted in a hole 99-1 infeed pawl 99.Slide bar 103 is disposed withinbarrel portion 29 ofapparatus 23 between ribs 31-1 and 31-3 ofbody half 31 and is movable back and forth byslider 77. Anactuator 107 is disposed in arecess 104 inslide bar 103 for depressing abutton 109 on a second switch 111 which is mounted onpins 113 integrally formed onright half 31 of casing 25.Slide bar 103 is shaped to further include a recess 103-2 having a front wall 103-3 and a back wall 103-4 and a projection 103-5.Slider 77 includes a projection 77-1 which is used to moveslide bar 103 back and forth as will hereinafter be explained.Actuator 107 is sized smaller thanrecess 104 so that it can move back and forth a small amount inrecess 104 to provide for additional overtravel.

The mechanism ingun 23 operates in the following manner.

When the mechanism ingun 23 is at rest in a "home" position, as shown in Fig. 15,rear end 115 of atop projection 117 onslider 77 is abuttingrear stop 91 in casing 25. Asdrive shaft 61 ofDC motor 59 rotatesclockwise slider 77 is moved in a forward direction as indicated by arrow C in FIGS. 15 and 15A. When projection 77-1 onslider 77 comes into contact with front 103-3 of recess 103-2 onslide bar 103 it will causeslide bar 103 to also advance in a forward direction causingfeed pawl 99 to rotate aboutpin 45 in a forward direction, pushing fastener stock 11 down intoguide groove 39.Slider 77 will move forward untilfront end 118 oftop projection 117 hitsfront stop 90. Rotation ofdrive shaft 61 in a counterclockwise direction will causeslider 77 to return to its original position. Asslider 77 moves back, projection 77-1 will hit up against rear projection 103-4 onslide bar 103, (see FIGS. 13 and 14), and carryslide bar 103 back with it to its original position.

The operation of the electric circuit portion ofapparatus 23 can be best understood with reference to FIG. 16.

As can be seen, the electric circuit, identified byreference numeral 123, comprisesfirst switch 55,DC motor 59 and second switch 111.First switch 55 and second switch 111 are both normally closed, single pole, double throw switches. The common terminal 55-1 ofswitch 55 is connected to the negative terminal ofDC motor 59 while the common terminal 111-1 of switch 111 is connected to the positive terminal ofDC motor 59. Acapacitor 124 is coupled in parallel with battery input terminals 60-8 and 60-9 to provide a more efficient use of the current.

Withswitches 55 and 111 in their normally closed position there is no current flowing throughDC motor 59. Whentrigger 37 is squeezed,projection 51 at the bottom oftrigger 37 will depressbutton 53 onfirst switch 55 causingswitch 55 to move from a normally closed position to a normally open position. This will cause current to flow throughDC motor 59 in a path shown by dashed lines 120-1. This current flow throughDC motor 59 will causeshaft 61 ofmotor 59 to rotate in a clockwise direction which in turn will causeslider 77 to move in a forward direction toward the front end ofbarrel portion 29, eventually engaging and carrying with it slidebar 103.

Just beforeslider 77 hits stop 90,detent 107 onslide bar 103 will push down against and depress theactuator button 115 on switch 111 causing switch 111 to move from a normally closed state to a normally open state.

At the same time asslider 77 hits stop 90, the last tooth 79-1 onrack 79 will be in engagement withspur gear 75. Continued movement ofrack 79 in a forward direction, will be free movement sincerack 77 is no longer coupled to spurgear 75. This movement will compressspring 81. Sincespring 81 is a compression spring it will tend to reextend, pushingrack 79 back to its position prior to any free movement so that the first tooth onrack 79 is reengaged withspur gear 75.

Withswitch 55 in an open position and switch 111 in an open position there will be a dynamic braking loop which will quickly bringmotor 59 to a stop.

Upon release oftrigger 37,switch 55 will return to a normally closed position and current will flow throughmotor 59 in a path shown by dashed arrows 120-2 causingdrive shaft 61 ofmotor 59 to rotate counterclockwise. This in turn will causeslider 77 to return to its original "home" position carrying with it slidebar 103. Asslide bar 103 moves back it will releaseswitch button 109 returning switch 111 to a normally closed position.Slider 77 will stop when it hitsrear stop 91. Momentum will cause continued free movement ofrack 79.Compression spring 83 will pushrack 79 back into engagement withspur gear 75.

As can be appreciated, oncemotor 59 is rotating clockwise causing slider to move in a forward direction it will not be reversed untilbutton 109 on switch 111 is depressed. However,button 109 will not be depressed unlessslider 77 moves forward sufficiently so that it engagesslide bar 103 and carries slide bar with it so thatactuator 107 can contactbutton 109 andpush button 109 down. In the event of a jam, such as by misalignment of a fastener in the needle,slider 77 may be prevented from moving forward to the point whereslide bar 103 is moved sufficiently forward so thatactuator 107 can depressbutton 109. To solve this problem arelease button 125 is provided.Button 125 enables a user to manually pushslide bar 103 forward so thatactuator 107 can be brought into contact withbutton 109 andpush button 109 down.Button 125 includes a base 125-1 and a projection 125-2. Base 125-1 is slidably mounted inbody half 31 between ribs 31-2 and 31-3 in back of projection 103-5 onslide bar 103. Projection 125-2 extends up through a longitudinal slot 31-6 in body half 31 (See Fig. 15A). Whenbutton 125 is pushed forward, base 125-1 will hit up against projection 103-5 onslide bar 103 and pushslide bar 103 forward to the point whereactuator 107 pushesbutton 109 down. Once this occursmotor 59 will be reversed movingslider 77 and henceejector rod 59 back away fromneedle 40.Needle 40 can then be easily removed fromapparatus 23 and the fastener causing the jam removed fromneedle 40.

Instead of one single pole double throw switch, switch 55 could be replaced by a pair of single pole single throw switches, one normally open and the other normally closed, with both switches being mechanically ganged together. Switch 111 could also be replaced by a pair of single pole single throw switches constructed and coupled together to function as switch 111.

Also, instead of shortening the rack to disengage the motor and drive gear from the slider at the end of its limited travel, overtravel can be achieved removing an arcuate segment of teeth from the spur gear or by providing for alternate engagement and disengagement of the spur and worm gears radially at a common pressure point using a spring loaded projection on one of the gears and a detent on the other gear.

In FIGS. 17-19 are shown front, top and side views of a modification ofbattery pack 60, the modification being identified byreference numeral 124.Battery pack 124 includes 6 batteries 124-1 through 124-6 which are stacked horizontally rather than vertically.Battery pack 124 includes acontainer 125 having anopening 127 in the side in which is disposed a switchtype charging receptacle 129. The circuit diagram forbattery pack 124 is shown in FIG. 20. The circuit includescharge voltage receptacle 129.Receptacle 129 has a positive terminal 131-2, a fixed negative terminal 131-3 and a normally closed terminal 131-4. Circuit also includes a junction 131-5, output terminals 131-6 and 131-7.Circuit 124 operates the same way as inbattery pack 60.Battery pack 124 is charged throughreceptacle 129.

Instead of being separate elements,actuator 107 andslide bar 103 can be made a unitary structure, if so desired. An example of a combined actuator and slide bar is shown in FIG. 21 and identified byreference numeral 135. Combination actuator andslide bar 135 is an elongated member shaped to include a recess 135-1 similar to projection 135-2 similar to projection 135-2 similar to projection 103-5. However, instead ofrecess 104, combination slide bar andactuator 135 includes a projection 135-3 fordepressing button 109 on switch 111.

In FIG. 22 there is shown an enlarged view of a modification ofactuator 107, the modified actuator being identified byreference numeral 137.Actuator 137 includes a channel shaped base 137-1 and a projection 137-2. Base 137-1 rides on rib 31-5 while projection 137-2 will depress botton 109 whenactuator 137 is properly positioned.

The embodiments of the present invention described above are intended to be merely exemplary and those skilled in the art shall be able to make numerous variations and modifications to it without departing from the spirit of the present invention. All such variations and modifications are intended to be within the scope of the present invention as defined by the appended claims.

Claims (10)

What is claimed is:

1. Apparatus for dispensing plastic fasteners from fastener stock, said apparatus comprising:

a casing,

a hollow needle mounted on said casing, said hollow needle having an inlet opening,

a guide groove in said casing for receiving fastener stock, said guide groove being in communication with said inlet opening in said hollow needle,

a feeder element for intermittently advancing fastener stock loaded into said guide groove,

an ejector rod for pushing plastic fasteners from said fastener stock through and out of said hollow needle one at a time, said ejector rod being mounted on said slider,

an electric motor for driving said ejector rod and said feeder element, said electric motor having a drive shaft,

a converter assembly for converting rotary motion of the drive shaft of said motor into linear motion, said converter including:

a worm mounted on the drive shaft of the electric motor,

a slider,

rack mounted on the slider,

a worm gear in engagement with the worm, and

a spur gear in engagement with the rack and coupled to the worm gear, and

control means for controlling the operation of said electric motor so as to produce intermittent reciprocating linear movement of said ejector rod.

2. The apparatus of claim 1, wherein said rack is slidably mounted on said slider and is sized to provide for overtravel.

3. The apparatus of claim 2, wherein springs are provided for reengaging said rack with said spur gear after overtravel of said rack.

4. The apparatus of claim 3, wherein said spur gear is loosely coupled to said worm gear.

5. The apparatus of claim 4, wherein said control means includes a first switch and said apparatus includes a hand actuated trigger for operating said first switch.

6. The apparatus of claim 4, wherein said control means includes a second switch and said apparatus further includes a slide bar slidably mounted in said casing and movable by said switch and an actuator movable by said slide bar for actuating said second switch.

7. The apparatus of claim 6 and further including a release button for manually moving said slide bar to bring said actuator into engagement with said second switch.

8. The apparatus of claim 6, wherein said actuator is separate from said slide bar and movable by said slide bar.

9. The apparatus of claim 6, wherein said actuator and said slide bar are a unitary structure.

10. The apparatus of claim 1 and further including a battery pack for powering said electric motor.

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